Lipids and essential fatty acids in the nutrition of Penaeus monodon larvae

Abstract only.Total lipid levels and fatty acid distribution during larval development of Penaeus monodon were determined. Larvae were cultured utilizing standard rearing procedures and feeding schemes adopted by the Crustacean Hatchery of SEAFDEC Aquaculture Department in Tigbauan, Iloilo, Philippines. At each developmental stage (spawned egg, nauplius, protozoea, mysis, postlarva), samples were collected for biochemical analysis. Lipid content decreased with developmental stage (from egg to postlarva), indicating utilization of lipids as energy source during larval development and metamorphosis. The major fatty acids in the egg lipid were 16:0 (palmitic), 16:1 (palmitoleic), 18:0 (stearic), 18:1 (oleic), 18:3 (linolenic), 20:4 (arachidonic), 20:5 (eicosapentaenoic), and 22:6 (docosahexa-enoic acids. As the larvae developed, levels of 16:1 and 18:1 fatty acids decreased with a corresponding increase in polyunsaturated fatty acids (PUFA), particularly 20:5ω3 and 22:6ω3. These indicate the importance of PUFA as dietary components. Comparison was made between fatty acid changes during larval development and the fatty acid constituents of commonly used larval feeds (algae, rotifer, brine shrimp, egg yolk) for P. monodon. The algae and zooplankton were found to contain 20:5ω3, while egg yolk was high in total lipids but low in polyunsaturates. Most larval diets were deficient in 22:6ω3 fatty acid. Crustaceans have been shown to have a limited capacity to biosynthesize long-chain PUFA; these have to be provided in their diet. These essential fatty acids must be available in appropriate amounts to ensure successful larval development and survival

Effects of diet on reproductive performance of ablated Penaeus monodon broodstock

Abstract only.Four practical diets were compared for their effects upon ovarian maturation and spawning of ablated Penaeus monodon broodstock. Diets were formulated based upon the fatty acid profile of wild P. monodon. Diets 1 and 3 were cod liver oil-based while Diets 2 and 4 were soybean oil-based. Experimental treatments consisted of each of the formulated diets given in combination with natural food (squid, mussel, and annelids). An all-natural diet served as control. The fatty acid composition and total lipid content of the diets and of P. monodon fed with these diets were assessed. Reproductive performance was evaluated in terms of number of spawnings, fecundity, egg and nauplii production and hatching rate of eggs. Broodstock response was best in Diet 1 and comparable with the control, followed by Diets 3 and 4, and was poorest in Diet 2. Broodstock performance appeared to be related to the fatty acid pattern of the diet. All pelleted diets contained similar levels of total lipids. However, there were differences in amounts of important polyunsaturated fatty acids (PUFA): 20:4ω6 (arachidonic), 20:5ω3 (eicosapentaenoic) and 22:6ω3 (docosahexaenoic) acids. The fatty acid profiles of Diets 1 and 3 more closely resemble the profile of maturing ovaries of wild P. monodon; the PUFA content of these diets and ω3/ω6 ratios were higher compared to Diets 2 and 4. Diet 2, showing the poorest profile among the diets, was low in ω3/ω6 ratio and contained minimal levels of PUFA

Evaluation of fish protein concentrate and lactic yeast as protein sources for shrimp feeds.

Protein sources, hydrolyzed fish protein concentrate and plasmolyzed lactic yeast, were used to partially replace fish meal and soybean meal, respectively, in a basal diet (diet 1) at these levels; 5% fish protein concentrate + 5% lactic yeast (diet 2), 5% fish protein concentrate (diet 3), and 5% lactic yeast (diet 4). A commercial diet was used as control. Diets were fed to Penaeus monodon postlarvae in an eight-week feeding trial in tanks. Parameters measured to determine diet efficiency were weight gain, survival, mass weight and feed conversion efficiency. Growth rates of shrimp postlarvae fed diets 2 and 4 were similar to those of the basal and commercial diets but significantly higher (P0.05) from diets 1, 2, and 4. Performance in terms of mass weights gave no significant differences among treatments. Field-testing of the diets showed that both fish protein concentrate and lactic yeast can support shrimp production in brackishwater ponds

Commercial evaluation of monosex pond culture of the mud crab Scylla species at three stocking densities in the Philippines

The effects of three levels of stocking density (0.5, 1.5 or 3.0 m−2) and monosex culture (male or female) on the growth, apparent feed conversion ratio (FCR), survival, and production of mixed species of mud crabs, Scylla serrata and S. tranquebarica, were investigated. The juvenile crabs were stocked in 150 m2 earthen ponds with Gracilariopsis bailinae as shelter and fed a mixed diet of 75% fresh mussel flesh and 25% fish bycatch. There was no interaction between stocking density levels and monosex culture (P0.05). Male crabs attained significantly higher (P0.05). Highest return on investment (ROI) and lowest production cost were obtained from 0.5 m−2. Partial budgeting analysis showed that no net benefit accrued from stocking beyond 1.5 m−2. Both male or female monosex cultures gave high net revenue and ROI of more than 100%. Results suggest that the culture of male or female mud crabs at 0.5–1.5 m−2 is economically viable but male monosex culture is more profitable

International study on <i>Artemia</i> : 25. Factors determining the nutritional effectiveness of <i>Artemia</i> : the relative impact of chlorinated hydrocarbons and essential fatty acids in San Francisco Bay and San Pablo Bay <i>Artemia</i>

Different Artemia cyst samples harvested from the San Francisco and the San Pablo Bay regions (California, USA), and suspect because of their poor nutritional performance in fish and crustacean farming, have been analyzed for their chlorinated hydrocarbon and fatty acid content. These results have been correlated with survival, growth, and biomass production of larvae of the marine crustacean Mysidopsis bahia Molenock fed those different Artemia in a standard culture test. Differences in chlorinated hydrocarbon content do not correlate with differences in mysid culture performance. Fatty acid profiles reveal three groups of Artemia batches with high, intermediate, and low levels of the highly unsaturated fatty acid 20:5omega3. The production yield of the mysid larvae could be correlated with the relative level of the 20:5omega3 fatty acid in the Artemia nauplii